1. Field of the Invention
This invention relates to an apparatus for measuring defects such as substrate fractures or internal cracks in relation to samples such as material substrates (photo-voltaic cell, polycrystalline silicon substrate), and particularly to a measuring apparatus for improving reproducibility of measuring operations and operating efficiency and improving accuracy of defect determination while doing little damage to the sample.
2. Description of the Related Art
Conventionally, there is an apparatus disclosed in, for example, JP-A-7-113791 as a measuring apparatus for speedily objectively evaluating uniformity of samples without doing damage to samples such as material substrates.
FIG. 9 is a block diagram showing a uniformity measuring apparatus of the samples. This measuring apparatus comprises a vibrator 102 for applying vibration to the end of a flat plate sample 101, a first vibration sensor 103 which is spaced a predetermined distance away from the applied vibration portion of the vibrator 102 and detects the vibration transferring the sample 101, and a second vibration sensor 104 which is spaced a predetermined distance away from the vibration sensor 103 and detects the vibration transferring to the sample 101.
The vibration applied by the vibrator 102 is transferred from the applied vibration portion of the sample 101 to the other end direction and is detected by the first and second vibration sensors 103 and 104. Vibration detection signals detected by the first and second vibration sensors 103 and 104, respectively, are fed to filters 105 and 106 for eliminating noise signals and selecting a signal with a predetermined frequency, and are amplified by amplifiers 107 and 108. The detection signal from the vibration sensor 103 is fed to a terminal of a channel 1 of an oscilloscope 109 and the detection signal from the second vibration sensor 104 is fed to a terminal of a channel 2 of the oscilloscope 109 and the detection signals are respectively displayed. Then, uniformity of the sample 101 can be evaluated by calculating a difference in vibration transfer time or a difference in transfer speed based on each of the detection signals displayed on the oscilloscope 109.
In the conventional apparatus described above, however, a fixing method of the sample 101, a positioning method of the sample 101 and the vibrator 102, and an applied vibration point of the vibrator 102 to the sample 101 were not disclosed at all. On the contrary, depending on determination of the fixing method, the positioning method and the applied vibration point described above, there was the possibility of causing damage to the sample due to the applied vibration, a decrease in detection accuracy of defect measurement and a decrease in operating efficiency.
The invention is implemented to solve such problems, and it is an object of the invention to provide an apparatus for measuring defects of a sample capable of improving mounting operations of the sample or a vibrator and improving accuracy of defect measurement and making an objective evaluation without doing damage to the sample.
According to a first aspect of the invention, there is provided an apparatus for measuring defects of a sample, comprising an inspection jig including a sample mounting portion for mounting the sample, a vibrator for applying vibration to the sample, and a sound collector for collecting a vibration sound when the vibration is applied to the sample by this vibrator; and a sound detector for conducting frequency analysis of the vibration sound collected by the sound collector, and the sample is pinched and fixed by a contact surface of the sound collector and a fixing part with a contact area similar to this contact surface when the sample is mounted in the sample mounting portion.
According to a second aspect of the invention, there is provided an apparatus for measuring defects of a sample, comprising an inspection jig including a sample mounting portion for mounting the sample, a vibrator for applying vibration to the sample, and a sound collector for collecting a vibration sound when the vibration is applied to the sample by this vibrator; and a sound detector for conducting frequency analysis of the vibration sound collected by the sound collector, and a fixing part for fixing the sample in the sample mounting portion is made of a cushioning material and the sample mounting portion is made movable in relation to an applied vibration direction of the sample.
According to a third aspect of the invention, there is provided an apparatus for measuring defects of a sample, comprising an inspection jig including a sample mounting portion for mounting the sample, a vibrator for applying vibration to the sample, and a sound collector for collecting a vibration sound when the vibration is applied to the sample by this vibrator; and a sound detector for conducting frequency analysis of the vibration sound collected by the sound collector, and the sample is resiliently pinched and fixed by the sound collector of the sample mounting portion and a fixing part.
In the invention, a surface having small unevenness of the sample is set to the contact side of the sound collector of the sample mounting portion.
In the invention, an applied point of the vibrator is set to a surface which is in the vicinity of the center of the sample and has no unevenness.
In the invention, a jig for keeping impact force and a release point of the vibrator constant is provided.
According to a fourth aspect of the invention, there is provided a method for measuring defects of a sample, comprising the steps of pinching and fixing the sample by a contact surface of a sound collector of a sample mounting portion and a fixing part with a contact area similar to this contact surface, applying vibration to the sample fixed in the sample mounting portion by a vibrator, collecting a vibration sound when the vibration is applied to the sample on the time series by the sound collector, and conducting frequency analysis of the vibration sound collected by the sound collector.
According to a fifth aspect of the invention, there is provided a method for measuring defects of a sample, comprising the steps of pinching and fixing the sample by a sound collector of a sample mounting portion movable in relation to an applied vibration direction of the sample and a fixing part made of a cushioning material, applying vibration to the sample fixed in the sample mounting portion by a vibrator, collecting a vibration sound when the vibration is applied to the sample on the time series by the sound collector, and conducting frequency analysis of the vibration sound collected by the sound collector.
According to a sixth aspect of the invention, there is provided a method for measuring defects of a sample, comprising the steps of resiliently pinching and fixing the sample by a sound collector of a sample mounting portion and a fixing part, applying vibration to the sample fixed in the sample mounting portion by a vibrator, collecting a vibration sound when the vibration is applied to the sample on the time series by the sound collector, and conducting frequency analysis of the vibration sound collected by the sound collector.